The present disclosure relates generally to valves and associated systems and methods. In some instances, embodiments of the present disclosure are configured to be part of an intraocular pressure (IOP) control system for use in ophthalmic treatments.
Glaucoma, a group of eye diseases affecting the retina and optic nerve, is one of the leading causes of blindness worldwide. Most forms of glaucoma result when the IOP increases to pressures above normal for prolonged periods of time. IOP can increase due to high resistance to the drainage of the aqueous humor relative to its production. Left untreated, an elevated IOP causes irreversible damage to the optic nerve and retinal fibers resulting in a progressive, permanent loss of vision.
FIG. 1 is a diagram of the front portion of an eye that helps to explain the processes of glaucoma. In FIG. 1, representations of the lens 10, cornea 20, iris 30, ciliary body 40, trabecular meshwork 50, and Schlemm's canal 60 are pictured. Anatomically, the anterior segment of the eye includes the structures that cause elevated IOP which may lead to glaucoma. The ciliary body 40 continuously produces aqueous humor, the clear fluid that fills the anterior segment of the eye (the space between the cornea and lens, or anterior chamber 70). The aqueous humor flows out of the anterior chamber 70 through the trabecular meshwork 50 into Schlemm's canal 60 and the uveoscleral pathways, both of which contribute to the aqueous humor drainage system. The trabecular meshwork may act as a filter, restricting the outflow of aqueous humor and generating a back pressure that directly relates to the IOP. The two arrows in the anterior segment of FIG. 1 show the flow of aqueous humor from the ciliary bodies 40, over the lens 10, over the iris 30, through the trabecular meshwork 50, and into Schlemm's canal 60 and its collector channels. The delicate balance between the production and drainage of aqueous humor determines the eye's IOP.
One method of treating glaucoma includes implanting a drainage device in a patient's eye. The drainage device allows fluid to flow from the anterior chamber of the eye to a drainage site, relieving pressure in the eye and thus lowering IOP. Once the drainage device is implanted, the body may form a bleb, or fluid-filled space surrounded by scar tissue, at the drainage site into which aqueous humor flows via a drainage tube. In order to provide desired treatments to patients, it may be important to regulate the flow of aqueous humor thorough the drainage device into the drainage site.
The system and methods disclosed herein overcome one or more of the deficiencies of the prior art.